1. Field of the Invention
The present invention relates to a contact lens care system for cleaning and disinfecting contact lenses, and to the method therefor. More particularly, the contact lens care system is a multi-electrode device which utilizes the principles of electrolysis and electrophoresis to both disinfect and clean contact lenses.
2. Description of the Related Art
It is particularly important that so-called soft contact lenses be kept sterile, because they tend to cause infections in the eye if they are not periodically disinfected.
Past methods of disinfecting such lenses have involved such cumbersome steps as boiling them for a predetermined length of time, or immersing them in a disinfecting solution, particularly hydrogen peroxide solutions. The latter method also requires immersing the lenses in a neutralizing or rinsing solution to remove the disinfecting solution from the lenses, because this solution can be highly irritating to the eye.
These methods suffer from various drawbacks, for example the lens disinfection unit may be cumbersome to use, since it may require the insertion and removal of the lens holder several times during the course of the process. Additionally, the user may forget to neutralize the lenses after disinfection, or confuse the disinfecting and rinsing solutions with one another, since both solutions are usually clear solutions. Needless to say, it is extremely dangerous to insert into one's eye a contact lens which has not had the disinfecting solution entirely removed.
Contact lenses must also be cleaned to remove contaminants from the lenses such as proteinaceous substances, and methods for cleaning contact lenses to remove these substances include the immersion of the lenses in surface active agents (i.e. soaps), enzymes, etc. These methods typically require that the cleaning solution be rinsed from the lenses, and the methods typically do not accomplish a satisfactory disinfection of the lenses.
Methods for cleaning contact lenses using an electrophoretic system have been known, such as those described in U.S. Pat. Nos. 4,921,544 and 4,732,185, however these methods have not proved to be completely satisfactory. These methods involve the immersion of the contact lenses in a buffer solution, and the creation of an electric field in the solution by a pair of spaced electrodes. Contaminants on the lenses such as proteins become charged and are attracted to the oppositely charged electrode, thereby cleaning the lenses.
Some drawbacks to these methods are that in order to disinfect the lenses, a disinfecting agent is typically required to be added to the buffer solution. As in the above-described methods, the disinfecting agent must be neutralized or rinsed from the lenses before insertion into the eye. Other drawbacks are, for example, that protein may be accumulated on the electrodes during electrolysis, and that a lengthy disinfection time may be needed.
Methods for disinfecting contact lenses using an electrolytic system have been known, such as proposed in Japanese Patent Publication No. 60-2055, however these methods have not proved entirely satisfactory. These methods involve the creation of a disinfecting solution by the electrolysis of a saline solution to produce chlorine (Cl.sub.2). Such methods are ineffective in completely removing proteinaceous materials from the contact lenses so that surface active agents, enzymes, etc. are typically needed to clean the lenses. The lenses must also be rinsed at the completion of that type of disinfecting process before insertion in the eye of the wearer to remove the chlorine.
Other known methods for cleaning contact lenses using the principle of electrolysis include the method proposed in Japanese Patent Publication 63-254416. That method uses a multi-electrode device which cleans contact lenses by the electrolysis of a physiologic saline solution to produce a high pH solution in the well containing the contact lenses. The highly alkaline solution dissolves the proteinaceous substances on the lenses, and an ultrasound cleaning device is used to help remove these substances from the lens surfaces. After cleaning of the lenses, the alkaline solution is then neutralized by reversing the polarity of the electrodes, thereby avoiding the need of rinsing or neutralizing the alkaline solution on the lenses before insertion in the eyes. This method does not disinfect the contact lenses.